Grate



Sept. 11, 1945.

R. L. BEERS GRATE Filed Nov. 13, 1945 2 Sheets-Sheet l INVENTOR.

ROYCE L.BEERS I BY imlllllllllllllllllllllfil F IGZ.

' ATTORNEYS Sept. 11, 1945. R. L. BEERS 2,384,433

GRATE 7 Filed NOV. 13, 1943 2 Sheets-Sheet 2 M INVENTOR. Q ROYCELBEERS 5- ATTORNEYS Patented Sept. 11, 1945 GRATE Royce L. Beers, Birmingham, Mich, assignor to Detroit Stoker Company, Monroe, Mich, a corporation of Michigan Application November 13, 1943, Serial No. 510,178

7 Claims.

' The invention relates to grates for use in automatic stokers of that type where the fuel from a retort is fed downwardover an inclined grate section to an ash discharge at the outer end thereof. It is usual to longitudinally reciprocate certain of the grate bars to facilitate the feeding of the fuel thereover and in certain constructions this reciprocatory movement is imparted to groups of individual bars. It is also usual to cool the bars by currents of air flowing on the underside thereof, the heated air being finally discharged between grate bars into the fuel bed resting thereon to support combustion.

It is the object of the invention to obtain improved means for cooling the grate bars and for controlling the discharge of the heated air through the grate.

More particularly, it is an object to obtain a construction applicable to grate bars arranged in groups. With these objects in view the invention consists in the construction as hereinafter set forth.

In the drawings:

Fig. l is a vertical cross section through a portion of a stoker having grates of my improved construction;

V Fig. 2 is a diagrammatic end elevation of the grate sections as viewed from the retort;

Fig. 3 is a side'elevation of one of the individual grate bars;

Fig. 3A is a top plan view thereof;

Fig. 3B is an end elevation;

Fig, 3C is a section on line 3C3C, Fig, 3;

Fig. 4 is a side elevation of a companion bar;

Fig. 4A is a plan view thereof;

Fig. 4B is a cross section on line 43-43, Fig, 4;

Fig. 5 is a cross section through a series of bars connected together to form a group; and

Fig. 6 is a perspective view showing a small portion of the companion bars.

As illustrated in Fig. 1, A is the retort sup- Ported by a beam B resting upon a wall C. D is one of the grate sections which at its inner end is slidably supported on the retort A and at its outer end upon a beam E resting upon a wall F. G is a rockable ash discharge grate member at the outer end of the section D and H is the outer furnace wall. The wall C and a companion wall on the opposite side of the retort (not shown) enclose a central air chamber I beneath the retort and portions of the grate resting thereon. Between the walls C and F is a low pressure air chamber I which extends beneath the greater portion of the grate.

In certain constructions heretofore used the individual grate bars have been hollow, receiving air from the high pressure chamber and discharging. it into the low pressure chamber while from the latter air passes upward between the individual grate bars into the fuel bed supported thereon. Such construction is not satisfactory where a plurality of grate bars are attached to each other to form a group and I have, therefore, devised an improved and simplified construction as follows.

The grate sections D are formed of a series of a grate bars J and K alternating with each other. Each of these bars has a fuel supporting top flange and a depending wall at the same side thereof so that when the two bars are placed together they will form three sides of an air channel. In the bar J the fuel supporting flange J' is imperforate but it is formed with a series of steps J on its upper face which are substantially horizontal whereas the bar inclines downward from its inner to it outer end. The bar J has the depending flange J The bar K is formed with a series of projecting flanges K constituting the fuel supporting steps but these flanges are vertically spaced and overlap each other. This will leave substantially rectangular air channels K between the flanges K' through which air is discharged laterally into the fuel resting .on the steps. The bar K also has the depending flange K and at its inner end a flange K forming a portion of the wall of theretort. Channels K in the flange K provide for discharge of air into the retort. Both the 'bars J and K are provided with bearings for engaging rock levers L which impart reciprocatory movement thereto. In the bar J the bearing J which engages the lever extends laterally from the vertical flange J and a flange J extends from this bearing longitudinally of the bar to form a fourth wall of the air channel within the bar. At the outer end of the flange J is an upwardly inclined portion J which diminishes the space between the same and the flan e J to restrict the opening through which air is discharged. The portion J also has a depending lug J which rests upon a flange L on the beam L thereby sealing between the high and low pressure chambers I and I. Thus, in operation, air from the high pressure chamber passes up: ward into the channel formed by the top flange J depending flange J and flanges J and J then downward into the low pressure chamber I. In the bar K the bearing K engages the lever and a flange K extend longitudinally to the depending lug K corresponding to the lug J of the "bar J. The remainder of the length of the bar tion D, the said bars are alternately arranged and a bolt M extending through aligned apertures in these bars clamp them together into a single unit.

With the construction as above described the section D is assembled with aseries of likesections D, D D which extend-thelength. of: the furnace. In operation, the rock levers L impart reciprocatory movement to the sections with the adjacent sections moving in opposite directions at the same time. This will cause the feedingof the fuel from the retort downward over the grate sections and the discharging 'of the-ash and clinker onto the rockable grate G. ,Duringithis feeding movement air from the high pressure chamber I will pass upward intothe spaces between the depending flanges J and K of adjacent bars and in the bar J will pass longitudinally between its upper flange 'J' and lower flanges J and J 6 finally discharging at the outer endof the bar into the low pressure air chamber I'. In the bar K only a small quantity of air passing upward from a high pressure chamber will pass through port K but this is suflicient to cool the inner end of the bar and also toblow off any deposit that may have dropped through the openings K However, as these openings extendlaterallythe amountof material that canv drop. therethrough is quite limited. In'the greaterportionofthe length ofthe bar K air passes upward fromlthe low pressure chamber and then is discharged laterally through the ports ,K into thefuel resting on thesteps. .;As the air thus passing. upward has previously passed through thelongitudinal channel. in the barJ where. it has..absorbed. heat from both bars, it will beheated suficientlyto better support combustion.

What I claim as my invention-is:

.1. The combinationwith a grate support .provided with-separatechambers adapted to contain air under different pressures, of a. grate on said.

support extending .over .said chambers and comprising a series of parallelly arranged gratebars of similar angle lcrosssection, each having a fuel supportingtop flange and a depending flange'at one side thereof, said bars together forming a;

three-sided .air. channel beneath .each top flange, and meanson alternate bars for completinga fourth side of the channel-extending. a portion of the length of thebar through which air passes from the high pressure chamber. to the. low-.pres-- sure chamber, the bars intermediate saidalternate bars being provided with openings through the top flanges thereof formingtuyres for..discharge of heated air fromthe low pressure chamher and channel into the fuel.

2. .A grate comprising a series of.para1lelly. arranged bars of similarangle cross section each having ,a fuel supporting top flangeand, a depending flange at one side thereof, said. bars together forming a-three-sidedair channel beneath the top flange of each. bar, and means on alternate bars for completing a fourth side to therair channel for a portion of the length of the bar to'direct air longitudinally therethrough and the bars-intermediate said alternate bars being provided with openings through the top flanges thereof forming tuyres for discharge of air from the channel into the fuel.

3. A grate comprising a series of parallelly arranged inclined bars of similar angle cross section, each having a fuel supporting top flange with a series of steps in the top face thereof and a depending flange at one side of said top flange, said barstogether forming a three-fsidedrair channel beneath the top flange of'each bar, arid means on alternate bars for completing a fourth side to the "air channel therebeneath extending a portion of the length of the bar to direct air longitudinally therethrough and the bars intermediate said al- -ternatebars being provided with openings through thertop. flange between the steps thereof forming tuyeres for discharge of heated air from the chan- *nel into. the fuel.

4. Agrate comprising a series of parallelly arrangedinclined bars of similar angle cross section, each having a fuelsupporting top-flange with a series of .steps inthe upper. face. thereofsandra depending flange. at one side of .:said: top: flange, said bars together forming .-a three-sided air channel beneath the top; fiangeon: each bar, the alternatebarg; of the: series having, thesuccessive steps thereof spaced. fromrand overlapping :each other to form air tuyeres therebetween, and means on. the bars of the series.intermediatesaid alternatewbars for-completing: a fourth' sideito the air channel for -a portion of .the lengththereof to direct .air longitudinally therethrough.

5. A grate comprising a unitformed of aseries of. parallelly arranged individual inclined .grate bars, each ;of similarwangle crosssection having afuel supporting top flange :andta depending flange at one side thereof andall of said rbars being secured. together therebyf forming-1a three- I sidedair channel beneatheach top flange,.the top flange of alternate bars ofthe-series'being formed of-successive spaced overlapping-steps with laterally discharging air tuyres therebetweennand means on the bars of the seriesz'other'thanrsaid alternate'barsfor completing :atforlrth side for' a portion of the .length of "the channel tthereof whereby cooling air is directed longitudinally through-said; completed channel portions and will pass therefrom downward' and eventuallyupward through" the intermediate channels and tuyeres communicating therewith.

6. A grate comprising aiunit'section'formed 'of a series of parallelly arranged individual inclined bars each" bar being of a similar angle cross section' with a topportion'for'supporting thefuel and 2. depending fiangeat'one side thereof, the topportion of alternate'bars being formed .by spaced overlapping flanges constituting fuel'supporting steps with tuyeres discharging-laterally intermediate said steps, and the bars of the series other than said alternatebars=each having an imperforate'top flange-and also being provided with a lower'flange for completing a fourth side of the channel'through a. portion of the length thereof "for directing air longitudinally through said channel,- the outer end'of said lower flange being bent upward to restrict'the discharge passage "for the air.

'7. 'Agrate comprisinga-unitformedof a series of connected parallelly arrangedinclined rgrate bars each being of similar. angle crosssectionhaving. an .upper fuel supporting portion and .adepending flange at one side thereof,:said bars together forming a three-sided air channel beneath each top portion, the :inner-ends of said bars the air channel, said last named flange being bent upward to restrict the opening at the end of the channel, the top of said bar having its upper face formed in a series of steps, and each bar of the series other than said alternate bars having the top portion thereof formed of spaced overlapping flanges constituting fuel supporting steps with air tuyres extending laterally therebetween.

ROYCE L. BEE-RS. 

